Fluid coupling



United States Patent() mesne assignments, to Liquid Drive Corporation,Holly, Mich., a corporation of Michigan l No. 2,878,645, dated Mar. 24,1959, Ser. No. 462,449,0ct. 15, 1954. Application for reissue Feb. 18,1960, Ser. No. 9,661

3 Claims. (Cl. 60-54) Matter enclosed `in heavy brackets appears in theoflginnl'patent but forms no part of this reissue specification; matterprinted in italics indicates the additions mit' Ivy reissue'.

This invention relates to fluid couplings and, more particularly, to animproved fluid coupling particularly adapted for use in transmittingrelatively high power at relatively high speeds.

Heretofore, when conventional fluid couplings have been employed totransmit relatively high power at relatively high speeds, failure of therotating elements of the couplings has occurred. In an effort toovercome these failures, various attempts have been made to strengthenthese elements by continued stiflening of the various elements, thestitfeningl being intended to reduce the stresses umltingfrom the highcentrifugal pressures of the fluid nithin-th'efluid couplingand the highcentrifugal stresses intheelements themselves. However'such ellortshavenotvl produced satisfactoryr results and the failures have continued.

An objectof the present invention is to overcome disadvantages in priorfluid couplings and to provide an improved fluid coupling which isparticularly adapted to transmit relatively high power at relativelyhigh speeds.

Another object of the invention is to provide an improvedfluid couplingincorporating improved means for separating torsional stresses in thefluid coupling from hydraulic stresses.

Another object ofthe invention is to provide an improved fluid couplingincorporating improved means for supporting the rotor vanes wherebyreversed moments or stress concentrations in the shell elements definingthe lluidcircuit are eliminated.

Another object of the invention is to provide an improved fluid couplingthat is economical to manufacture and assemble, durable, efficient andreliable in operation.

Another object of the invention is to provide an improved fluid couplingincorporating improved means for maintaining the yaxial dimensions ofthe fluid circuits subltantally constant.`

Another object of the invention is to provide an improved multiplecircuit fluid coupling incorporating improved means ^for transmittingpower to the primaryrotors-of the coupling.

Another object of the invention is to provide an irnproved uid couplingincorporating improved means for circulating fluid through the unit forcooling purposes.

Still another object of the invention is to provide an improved fluidcoupling incorporating improved means for controlling the speed andtorque of the unit and for rapidly disengaging the unit.

The above as well as other objects and advantages of the'presentinvention will become' apparent from' the following description, theappended claims andthe accompanying drawing wherein:

Figure 1 is a fragmentary, longitudinal, sectional .view of a'uidVcoupling embodying the present invention; and

Fig. 2 is' aY fragmentary, transverse, sectional viewof theuid'couplingillustrated in Fig. 1, taken on the line 2L-2`thereof.

to the drawing, the present inventionis shown ICC incorporated in atwin-circuit uid coupling, generally designated 10, particularly adaptedfor use in transmitting relatively high power at relatively high speeds,a1- though it will be understood that the present invention isapplicable to other uses. The fluid coupling 10 is comprised of ahousing l2 having an opening 14 in one end thereof adapted to receive aretainer ring 16. The retainer ring 16 carries a bearing 18 whichsupports a shaft 20, the shaft 20 constituting an extension of the driveshaft 22 of the fluid coupling. The bearing 18 is retained by a nut 24and washer 26, the nut 24 threadably engaging the axially outer endportion of the shaft 20. A closure member 28 is provided for the housing12 and is secured ,to the housing 12 by a bolt 30 that extends throughthe retaining ring 16 and a flange 31 provided on the closure member,and threadably engages the housing 12. The shaft 20 is mounted forrotation on one end portion of the driven shaft 32 of the fluidcoupling, a suitable bearing 34 being interposed between the shaft 20and the driven shaft 32. With such a construction, the shaft 20 is freeto rotate relative to the driven shaft 32 and is also free to rotaterelative to the housing 12.

A pair of coaxially aligned primary rotors or impellers 36 and 38 areprovided which including shell members 36a and 38a, respectively, thatdefine generally hemitoroidal chambers 40 and 42 that are disposed inspaced confronting relationship. A secondary rotor or runner 44 isprovided which is disposed coaxially between the impellers 36 and 38 andwhich includes a shell member 44a that defines a pair of generallyhemi-toroidal charnbers 46 and 48 that spacedly confront the chambers 40and 42, respectively, defined by the impeller shell members 36a and 38awhereby the chambers 40 and 46 and the chambers 48 and 42 define twinfluid circuits which serve to transmit power through the fluid coupling.

'Ihe runner shell member 44a includes a hub portion 50 that is splined,as at 52, to the driven shaft 32 so that axial movement of the drivenshaft 32 relative to the runner 44 is permitted. The impeller shellmember 36a includes a hub portion 54 which spacedly surrounds the hubportion 50 of the runner shell member 44a and which is secured to theshaft 20, as by bolts 56. In order that the axial dimensions of thefluid circuit may be maintained substantially constant so as to reducesurging within the fluid circuit, a thrust bearing 58 is providedbetween a radial face 59-provided on the shaft 20 and a radial face 60provided on the hub portion 54 of the impeller shell member 36a. Sincethe runner 44 is splined to the driven shaft 32, axial movement of thedriven shaft 32 relative to the rotors is permitted and, at the sametime, the axial dimensions of the fluid circuit are maintainedsubstantially constant.

The impeller shell member 38a includes a hub portion 60 which defines abore 62 through which the driven shaft 32 extends. A gear 64 is splinedon the axially outer end portion of the hub 60, as at 65, and the gear64 meshes with a ring gear 66 fixed to the drive shaft 22 of the fluidcoupling, the drive shaft 22 extending through an opening 64 in thehousing 12 coaxially aligned with the opening 14, and a suitable bearing66 being interposed between the housing and the drive shaft 22. The gear64 is retained by a nut 72 which threadably engages the axially outerend ofthe hub portion 60 of the impeller 38.

The impellers 36 and 38 also include a pluralityof radially extendingvanes 76 which are mounted in each of the chambers 40 and 42 of theimpellers 36 and 38, each of the vanes 76 having integral outwardlyprojecting tabs 78, 80 and 82. The tabs 78 of the varies 76 are fittedin slots 84 provided in each of the impeller shellmembers at a positionadjacent the hub portion-of A-the impeller shell member,

. is provided to of iluid under pressure interposed and the tabs 78 areretained by rings 86 so as to lock the vanes at the hub. The tabs 80 and82 are mounted in slots 88 and 90 provided in the central portions andperipheral portions, respectively, of

Ythe shell members 36a and 38a, and are retained by locking rings 92, 94and 96. The slots 84, 88 and 90 space the vanes tangentially andsufficient clearance is provided to permit distortion of the shellmembers with respect to the neighboring vane portions. With such aconstruction, alternate rigid and flexible sections in the` impellersare eliminated, thereby eliminating the possibility of reverse momentsor stress concentrations at the points where the vanes are joined to theperipheral due to the high'centrifugal forces portions of the impellerin the circuit when the and the high hydraulic pressures fluid couplingis in operation.

A plurality of radially extending vanes 98 are mounted in each of thechambers 46 and 48 of the runner shell member 44a, each of the vanes100, 102 and 104. The tabs 100 are fitted in slots 106 provided adjacentthe hub portion of the runner shell member 44a while the tabs 102 and104 are fitted in slots 108 and 110, respectively, provided in thecentral portions and the peripheral portions of the runner shell member44a. The tabs 100, 102 and 104 are retained by rings 112, 114, 116 and118 and the slots in which the tabs are disposed space the vanestangentially of the chambers 46 and 48 of the runner. Sufficientclearance permit distortion of the runner shell member with respect tothe neighboring vane portions, and, with such a construction, alternaterigid and flexible sections in the runner 44 are eliminated, therebyeliminating the possibility of reversed moments or stress concentrationsat the points where the vanes are joined to the runner.

The impeller shell member 36a is provided with a peripheral flangeportion 120 which projects axially outwardly toward the impeller 38 andspacedly encompasses the runner shell member 44a. As shown in Fig. 2,the flange portion 120 of the impeller shell member 36a is provided withradially extending involute serrations 121 and the flange portion 120 iskeyed to a peripheral flange portion 124 provided on the impeller shellmember 38a, the ange portion 124 projecting axially toward the impeller36 in spaced relationship with respect to the runner 44 and beingprovided with radially extending involute projections 125 Which arereceived in the serrations 121. An outer shell 126 is also providedwhich surounds the impellers 36 and 38 and the runner 44, the outershell including a main body portion 128 and a cover portion 130,threadably connected to the main body portion 128,

, as at 132. A suitable sealing ring 133 is also provided to insure afluid-tight connection therebetween. As

. shown in Figs. 1 and 2, the outer shell 126 is provided with integralangularly spaced keys 134 and is keyed to the flange portion 120 of theimpeller shell member 36a at angularly spaced points, keyways 135 beingprovided in the flange portion 120 to receive the keys 134. Fluidpassageways, such as 136 and 137, are provided between the areas atwhich the outer shell 126 is keyed to the flange portion 120, so that afluid path is provided which interconnects the chambers 138 and 140defined between the outer shell member 126 and the impellers 36 and 38.

A pipe fitting socket opening 142 is provided in the closure member 28,the socket opening communicating through the bore 144 of the shaft 20with a longitudinally extending passageway 146 provided in the drivenShaft A supply line 148 communicating with a source (not shown) isconnected to the socket opening 142, and a suitable sealing ring 150 isbetween the shaft 20 and a boss 152 provided on the closure member 20 toinsure a fluid-tight connection. The inner end portion of the passageway146 communicates with the twin fluid circuits defined by the '.1vchambers 40 and 46 and the chambers 48 and 42 through radiallyextending ports 154,

'an annular groove 156 provided in the runner 44, and ports 158, 160,162 and 164, the ports 160 and 164 discharging into the fluid circuitsthrough the spaces between the impellers 36 and 38 and the runner 44.The generally toroidal ud circuits are also connected with each otherthrough the annular space 166 between the peripheral flanges of theimpellers and the peripheral portions of the runner, and the fluidcircuits also communicate with the chambers 138 and 140 through ducts168 and 170. As previously mentioned, the chambers 138 and 140 areconnected with each other by passages, such as 136 and 137, between thekeyed areas of the peripheral flange 120 andthe outer shell 126.

In order to facilitate lubricating and cooling the rotating componentsof the fluid coupling, suitable ducts, such as 172, 174 and 176,communicating with the longitudinal passageway 146 in the driven shaft32 are also provided.

For the purpose of controlling the speed and torque of the fluidcoupling and to provide means for rapidly disengaging the unit, acontrol member, generally designated 178, is provided. The controlmember 178 functions to remove uid from the fluid circuits of the fluidcoupling and also functions to regulate the amount of fluid containedwithin the fluid circuits of the coupling. The control member 178 iscomprised of a plurality of radially extending vanes 180 which aremounted in ang-ularly spaced relationship on an integral hub 182. Thevanes 180 define radial passageways 184 which curve radially outwardinto the direction of rotation of the impellers, and the radial outerend portions of the pas- The radiallyinner end portions of thepassageways-184 communicate with an axially extending discharge opening188 through which the fluid is discharged from the control memberexteriorly of the outer shell 126. Means are also provided fortransmitting a torsional effort to the control member 178. In theembodiment of the invention illustrated, a brake drum 190 is providedhaving a brake lining 192 fixed to the inner surface thereof. -The brakelining is adapted to engage the hub portion 182 of the control memberwhen pressure is applied to the brake drum by any suitable orconventional means.

The control member 178 is mounted concentrically on the hub portion 60of the impeller 38 so that the vanes 180 are disposed in the chamber 140while the discharge openings 188 communicate with the exterior of theouter shell member 126. Suitable bearings 194 are provided between thehub 182 of the control member and the hub portion 60 of the impeller 38so that the control member is free to rotate about the laxis of the hubportion 60 of the impeller 38.

When the uid coupling is operating, the control member 178 will rotateat substantially the same speed that the fluid within the chamberrotates, assuming that no resisting torsional effort is applied to thecontrol member. The control member, rotating in this manner, will notalter the quantity of uid within the chamber 140 since, in order tochange the direction of the fluid velocity, it is necessary to apply aresisting force, assuming that bearing friction and the like areneglected. In order to discharge fluid from chamber 140, a resistingtorsional effort is applied to the control member 178 through the agencyof the brake drum 190 and lining 192. The torsional effort will resistthe tendency of the control member to rotate, thereby creating arelative velocity of the fluid to the control member. 4The direction ofthe relative velocity is changed by the contour of the vanes or passages184 and by the resisting force exerted in the uid by the vanes 180 orpassages 184. The change in the direction of the relative velocity isradially inward and results in a ow of fluid to the discharge opening188 from which the Huid is expelled from the control member. The productof the force against the vanes, developed by the direction of and theradius at which theforce'actsis equivalent to the resisting torsional"effort applied to the control member.

Consequently, to increase or decrease the rate of discharg an increasedo'r"decreased resisting torsional eort must be applied. From the abovedescription, it will be apparent that when a resisting torsional effortis applied, the control member will commencewto'empty'the iluid from thechamber 140 and will continue to empty the chamber until the innerdiameter of the rotating rim of the uid within the chamber 40 exceedsthe outer diameter of the control chamber. It will also be apparent thatcomplete declutching can be accomplished in a relatively short time andthat by adjusting or regulating the resisting torsional effort appliedto the control member, the quantity of iluid within the chamber .140 maybe regulated to vary the speed and torque of the unit.

In the operation of the uid coupling, power from a prime mover istransmitted to the iluid coupling through the drive shaft 22, the ringgear 66, and the gear 64 to the impeller 38. At the same time, lluidunder pressure is supplied to the fluid coupling through the supply line148, the longitudinal passageway 146, ports 154, annular groove 156, andports 158, 160, 162 and 164 to the fluid circuits deiined by thechambers 40 and 46 and the chambers 42 and 48. The power applied to theimpeller 38 is transmitted to the impeller 36 through the keyed flangeportions 124 and 120 of the impeller shell members. Since the outershell 126 is keyed to the peripheral iianges 120 and 124 in a mannerwhich permits radial movement of the outer shell, the outer shell issubjected to the high ilud pressures only and is not subjected totorsional stresses. At the same time, the flange portions 120 and 124joining the impellers are relieved of all hydraulic radial forces andare subjected only to torsional forces. Since the outer shell is keyedto the impellers, relative tangential movement between the outer shelland the impellers is prevented, and at the same time, the outer shell isprevented from moving axially relative to the impellers, the butt endsof the keys 134 engaging the ends of the keyways 135 which serve asabutment stops. From the above description it will be apparent thatbecause of the hydraulic balance achieved in the embodiment of theinvention illustrated, the torsional stresses are separated from thehydraulic stresses, thereby permitting the transmission of relativelyhigh power at relatively high speeds, which conditions may beencountered, for example in transmitting the power developed by a gasturbine.

Under normal operation, the uid which circulates through the unit willenter through the openings between the impellers and the runner at thecenter of the circuit proiile and overilow from the openings 200 and 202in the outer shell 126 at either end of the assembly, the overow beingreturned to the iluid source from a sump (not shown) provided in thehousing 12. Such a ow arrangement insures a change of iiuid with eachcircuit.

Since the vanes 76 and 96 of the impellers and the runner, respectively,are secured to the impeller shell members and the runner shell member ina manner which permits distortion of the impeller and runner shellmembers with respect to the neighboring vanes, the impeller shellmembers and the runner shell member are permitted to expand under theuniformly distributed hydraulic pressure and are, therefore, stressedevenly without reverse moments or stress concentrations.

It will be noted that a bearing support is provided on either side ofthe rotors, a piloted gear type of exible coupling being provided on oneside of the rotors and the rotors being supported radially by thebearings 134 and 18 on the other side, the spacing between the runnerand the impellers being maintained by the thrust bearing 58. The distalend of the driven shaft 32 may be conveniently supported by any desiredor conventional bearing means.

While a preferred embodiment of the invention has been shown anddescribed, it will be understood that various changes and "modifications'may be made without departing from the spirit of the invention.

What is claimed is:

1. In a iluid coupling, the combination including a -rst impeller,a'second impeller disposed in spaced substantially coaxial relationshipwith respect'to said first impeller, a runner interposed betweensaidfirst and second impellers, said impellers and said runner defininga plurality of fluid circuits, an outer shell member enveloping saidimpellers and said runner and defining a plurality of uid passagewaysbetween said outer shell member and said impellers, means connectingsaid fluid passageways with said circuits, means joining said impellers,said means joining said impellers being exposed to the fluid pressure insaid iiuid passageways and said circuits whereby said means joining saidimpellers is relieved of substantial hydraulic pressure differentialswhile subjected to torsional stresses, and means keying the centralportion only of said shell member to said impellers and permitting saidshell member to move radially outwardly relative to said impellers whensaid shell member is subjected to hydraulic pressures, the opposite endportions of said shell member being free to move relative to saidimpellers and said runner.

2. In a iluid coupling, the combination comprising a pair of impellerseach including a shell member defining an open-sided chamber, a runnerdisposed in substantially coaxial tandem relationship with respect tosaid impellers and including a shell member defining a pair of opensidedchambers spacedly confronting said impeller chambers whereby saidchambers define a plurality of fluid circuits, said impellers and runnerincluding a plurality of vane members in each of said chambers, slot andtab fastening means securing some of said vane members to said impellershell members in radially extending angularly spaced relationship andpermitting relative radial movement between said last-mentioned vanemembers and said impeller shell members, slot and tab fastening meanssecuring the remaining vane members to said runner shell member inradially extending angularly spaced relationship and permitting relativeradial movement between said remaining vane members and said runnershell member, an outer shell member enveloping said impellers and saidrunner and dening a plurality of fluid passageways between said outershell member and said impellers, means connecting said iluid passagewayswith said circuits, means joining said impellers, said means joiningsaid impellers being exposed to the iluid pressures in said uidpassageways and said circuits whereby said means joining said impellersis relieved of substantial hydraulic pressure differentials whensubjected to torsional stresses, and means keying the central portiononly of said shell member to said impellers and permitting said shellmember to move radially relative to said impellers when subjected tohydraulic pressures, the opposite end portions of said outer shellmember being free to move relative to said impellers and said runner.

3. In combination with a driving structure including a driving memberand an impeller drivable thereby, a driven structure including a runnerand a driven member drivable by the runner, said impeller and runnerhaving confronting coacting fluid circuit chamber portions and defittinga fluid coupling, a rotary casing including a .shell enveloping saidimpeller and runner and rotatably drivably keyed to one only of saidstructures, all portions of said shell being radially expansibleindependently of both of said structures.

References Cited in the le of this patent or the original patent UNITEDSTATES PATENTS 1,858,514 Lell May 17, 1932 1,859,607 Sinclair May 24,1932 (Other references on following page) Lv UNITE) STATES PATENTSSchaefer -i Apr. 29, 1941 Zeidler Oct. 21, 1947 Nutt Apr. 13, 1948 Dolzaet al Dec. 20, 1949 Palen et al Mar. 6. 1951 Mayner Dec. 30, 1952 RaneyJan. 6, 1953 8 Venstrom Sept, `1,5, 1953 Gleasman Aug. 24', 1954Chamberlain Oct. 12, 1954 English et al May 15, 1956 FOREIGN PATENTSFrance June 10. 1953

